Method of liquid-fuel heating



Nov. '18, 1930. M. A. POWERS METHOD OF LIQUID FUEL HEATING Original Filed'A g. 25, 1927 4Sh98tS-Sh98t l QQN [(3 INVENTOR fllz'limzAfomem' m g Y M ATTORNEY 5* 1930- A. :wwms fi' ii lfifi METHOD UF LIQUID FUEL HEATING Original Filed Aug. 25, 192? 4 Sheeis-$haei s 70 ifgi/? INVENTOR z'fzmAPswem BY @KZMM ATTORNEY NOV. 13, 1939. A POWERS 1,782,950

METHOD OF LIQUID FUEL HEATING Original Filed Aug. 25, 1927 4 Sheets-Sheet 4 "Wimp I l I INVENTOR M'lioiz A. fowezzr BY A a d; 7 M ATTORNE Iii-the possibility Patented Nov. 18, 1930 UNITED STATES PATENT OFFICE rrmron A. rownns, or NEW YORK, 1 N. Y., assronon, BY MESNE ASSIGNMENTS, To run rmxmv-nmaorr comrm, or person, MICHIGAN, A ooaroaarron or MICHIGAN unrnonor LIQUID-FUEL HEATING Originalapplication filed August 25, 1927, Serial No. 215,494. Divided and this application filed February 1, 1928. Serial No. 251,202.

V This application is filed as a division of my pending application Serial No. 215,494, filed August 25, 1927, and the subject-matter of this invention herein embodied relates gen- 5 erally to a method of burning liquid fuel. More specifically, it relates to a method of burning liquid fuel whereby an intimate combustible mixture of fuel and air is attained and burned in such a manner as to eliminate of cumulative carbon formation.

One of the difiiculties heretofore experi-. enced with liquid fuel burners is the excessive accumulation of carbon after-the burner has been in operation for a short time. When carbon once forms in the burner there is a.

corresponding tendency for the carbon to build up and increase in volume unless steps are taken for removing or consuming it. Such carbon formations greatly lower the heating efficiency of the burner, and if the gathering carbon is not removed, will eventually clog the burner, and prevent further operation. Another difiicult which has "3 stood in the way of a more wi espread adoption of automatically regulated li uid fuel burners is the fact that heretofore t ey have presented a complicated piece of mechanism, with many parts, and consequent ever presis reduced to a minimum, and if any carbon should chance to form and begin to accumulate at one rate of burnin it would be reduced as the burning rate 0 anges to another burning rate. Another object of the inven-- tion is to produce a burner with a high heat ing efficiency and with the least number of parts, thereby minimizing the possibility of the burner getting outof order.- Still another object is to produce an automatically controlled liquid fuel burner which is sturdy, simple of operation, and easily controlled by disclosure In accor ent possibility of getting out of order. They have also beenexpensive in first cost and expensive to operate. Further, present units the ordinary housewife. Anoth r object is onthe market at greatly reduced cost. Still another object is to produce a compact unit having no exposed parts, occupying a small amountof room space, neat in appearance and pleasing to the eye. I Other objects of. this invention. will be in part obvious and inpart pointed out as the proceeds. ance with this invention, copious streamsv of low pressure air are directed against a shallow pool of heated liquid fuel. Nozzles are provided for directing the streams of air, causing them to impinge and roll across the liquid surface until they are saturated with fuel vapors, then to rise upwardly to the to of the combustion chamber, curl over an again move downwardly,

completed by this spiraling and rolling action. The ignited wick initially heats the combustion chamber to some extent, causing the liquid fuel thereby to also become heated and fuel vapors to be given off. As more air nited wick extends itself to the liquid pool,

fuel vapor to be given off, increasing the rate of burning and the heat developed. Thus,

and fuel are supplied, the flame from the igcausing it to become further heated and more by controlling the rate of air flow and fuel I flow to the combustion chamber, the rate of burning and heat developed thereby can at all times be controlled. The invention contemplates the automatic maintenance of a predetermined liquid fuel level in the combustion chamber and the automatic control of the maximum and minimum rate of fuel flow incorrespondence with the maximum and minimum rate of air flow. .lhe inventionfurther contemplates the provision of adjusting devices for fixing this maximum and minimum relationship of air flow to fuel flow. The burner, in accordance with this invention, includes adjusting devices on the liquid fuel valve by which a minimum rate of flow of oil can always be maintained, to keep the ignited Wick feebly burning, and an oil flow rate above a fixed maximum can likewise be prevented. A magnetic device controls the rates of fuel flow from this maximum to minimum or vice versa. An electrical device operating the air valve is electrically connected in circuit with the magnet of the oil valve, so that an electric current passing through the circuit will operate the oil valve and; air valve automatically and in unison.

. The burner also embodies means for carryalong the fuel pool resulting in an intimate consequent perfect combustion.

The invention further contemplates an improved safety device whereby an excessive accumulation of liquid fuel in the combustion chamber or other parts of the burner will cause a safety valve to be operated to shut off the fuel supply automatically. Certain adjustments will then have to be made before operation of the burner can be resumed.

The burner is, furthermore, of few parts and quickly assembled for operation. The covering portions are readily removable to permit free access to regulator and control parts.

In order that a clearer understanding of my invention may be had, attention is hereby directed to the accompanying drawings, forming part of this application and illustrating certain possible embodiments of the invention.

Fi 1 is a top view of the burner embodyingtiis invention Fig. 2 is a vertical sectional view taken ipngitudinally of the burner on line 22 of Fig. 3 is avertical cross-sectional view of the reservoir block, showing the oil reser- Voir and oil flow control valves, and is taken on line 3'3 of Fig. l;

Fig. 4 is a vertical cross-sectional view of mixture of fuel vapors and incoming air with the combustion chamber with arrows showing the direction of the air flow, and is taken on line 4-4 of Fig. 1;

Fig. 5 is a side view of the air inlet to the blower housing and the automatic arrangement for operating the. air inlet valve; and Fig. 6 is a side view of the same device showing more clearly the telescoping collar for adjusting the size of the air openings.

Referring to the drawings, the burner genmemh ing out the various steps and burning operaerally comprises a base or supporting frame 1, a combustion chamber 2, a reservoir block 3 containing a liquid fuel reservoir 4, a float valve 5, and a liquid fuel control valve 6, a safety valve 7 a blower housing 8, a blower 9, a blower operating motor 10, an air valve 11, a hood member 12, and a cover member 13. y

The base or supporting frame 1 is preferably made as an integral casting with side walls 14. Inturned flanges 15 extend along the upper edge of the side walls. The corners of the base are cast into foot formations 16 with apertures therein for bolting the base to the floor. A hinged doorl'i' pivoted to swing upwardly closes one end of the base The reservoir block 3 is preferably made as a casting and is suspended at one end of the supporting frame by means of bolts 18 passing through the side flanges 15 of the base and integral flanges 19 extending laterally from the sides of the reservoir block. A

hollowed out portion in the reservoir block forms the oil reservoir 4 and another hollowed out portion contains the fuel control valve 6 and its operating mechanism. The

reservoir block has a liquid fuel intake pas sage 20 that extends from the inner end wall of the block horizontally into the block a short distance and there meets a vertical oil passage 21 extending from the top surface of the block. A clean out plug 22 closes the upper end of the vertical passage. The vertical oil passage extends a considerable distance into the block and then turns at an angle to form a horizontal oil passage 23 leading to and beneath the fuel reservoir and again turns to form a vertical oil passage 24, which enters and terminates at the bottom of the fuel reservoir. An enlarged oil passage 25 leads, from the bottom of the oil reservoir and beneath the fuel control valve cavity and forms therebeneath a miniature oil reservoir. A contracted oil passage 26 leads from the bottom of the miniature reservoir and its mouth is formed into a valve seat 27. Contracted oil passage 26 opens into a larger horizontal passage 28 which extends from the outer side wall of the block toward the front end wall, where it meets a vertical oil passage 29 which extends through the bottom of the block and is closed by plug 30. Another horizontal oil passage 31 extends from the outer end wall of the block and enters the vertical oil passage 29. The outer end of the horizontal passage 28 is closed by a removable clean out plug 32. Thus, it is seen that the reservoir block contains a continuous passage for conducting fuel oil from the inner end wall, where the oil enters the block, to'the fuel oil reservoir 4, to the fuel block, and vertical oil passage 29 opens at the bottom of the block, and by removal of clean out plugs 22, 32 and 30, respectively, closing their outer ends, a stream of air or liquid can be blown through the oil passage system to clean it of any clogging foreign matter. I

The combustion chamber 2, made of heatresisting metal, is cast into tubular form. It comprises a tray or belly portion 33 and a housing or back portion 34.' An upturned lip 35 along the front edge of the tray nor,- tion retains the liquid fuel deposited therein. Attaching lugs 36 at the other end of the tray portion have bolt receiving apertures 37 and metal mound formations 38 at their tip ends. An oil passage 39'leads from the tray interior to the outer end wall and terminates in a projecting boss 40 which seats within a cavity portion 41 surrounding the external end of oil passage 31 in the reservoir block. T he boss and cavity portions in the combustion chamber and reservoir block, respectively, keep the oil passages therein in correct alignment. A gasket member 42 may be inserted in the cavity portion, and when screw bolts 47, extending through the lug apertures and into the reservoir block, are tightened, the mound formations 38 contact with the front endwall of the reservoir block and cause the boss to seat firmly within the cavity and against the gasket member 42, resulting in a continuous oil con'ducting'passage from the reservoir block to the combustion chamber. Gasket member 42 also serves as a heat insulating medium. preventing heat generated in the combustion chamber from passing to the reservoir block and unduly heating the same. The tray portion has an upturned flange formation 43 serving as an end wall for the tray. A wick 44 extends the breadth of the tray portion and has a clip member 45 attached thereto which curls over the upper edge of the upturned flange 43 and secures the wick in position.

The housing portion 34 of the combustion chamber has a small opening 46 through which a match or other igniting device may be inserted to light the wick. A door 47" hinged for upwardly swinging movement closes the opening. The front edge of the housing portion is formed into an upturned nose 48 and has a ridge or rib 49 around its outer periphery for a purpose which will be described hereafter. The housing portion is formed of metal of considerable thickness and has a series of holes in longitudinal rows along its top and sides, forming nozzle apertures. Preferably, six rows of holes are used extending substantially the entire length of the top port-ion. The outside rows of holes 50 and 51, as shown in Figure 4, are sunk vertically into the back of the housing portion and in such a position as to be substantially in alignment with the interior surface of the side -.-inite direction.

walls. Thesefhliles may be one-fourth of an inch in diameter and on three-eighths inch centers, but applicant does not limit himself to the particular size or spacing'of the holes.

A second pair of rows of holes 52 and 53, further up on the housing portion, extend longitudinally thereof and in staggered relation to the aforementioned rows of holes 50 and 51, and may be of the same diameter and spacing. The longitudinal axes of holes 52 and are inclined outwardly to the vertical and toward the inner ends of holes 50 and 51. A third pair of rows of holes 54 and 55 are positioned longitudinally along the midline of the housing portion. These rows may be in staggered relation to each other and of difierent diameter and spacing than the rows of holes 50, 51, 52 or 53. The longitudinal axes of rows of holes 54 and 55 are more inclined than the axes of holes 52 and 53 and the inner ends of rows of holes 52 and 54, on the same side of the housing portion, diverge, as is well illustrated in Fig. 4. Thus, it is seen that the rows of holes are inclined at varying angles but always toward the sideg nw stream of air passing through them in a def- Laterally extending side flanges 56 may be formed integrally along the sides of the combustion chamber fo'na purpose to be hereinafter disclosed. Lugs 57 may be formed on the combustion chamber to receive the pintle rod 58, to which door l7 is pivoted.

Float mm 5 in the fuel oil chamber, as illustrated in Fig. 3, fixes the maximum level to which the oil can rise on. the tray portion of the combustion chamber. A valve seat member 59 having a threaded periphery 6O screws into the open end of the vertical oil passage- 24 and has a vertical passage therein up through which the oil rises on its Way to the oil reservoir. The top of the hollow portion converges into a constricted portion which is shaped to form a valve seat 62 for a needle valve 63. A suitable gasket 64 may be disposed between the valve seat member and the bottom of the oil reservoir to make a non-leak connection. A collar portion 65 formed integrally with the valve seat member surrounds the needle valve to guide it into seating position. A cover member 66 seats over the top of the oil reservoir and has a central threaded aperture into which a hollow plug member 67 screws. A collar member 68, having a circumferential groove 69 and an upwardly extending cylindrical portion 70, is secured to the upper end of the needle valve 63. The hollow plug member 67 surrounds the cylindrical portion 70 and serves as a guide for the upperend of the needle valve 63. A cap member 71 is threaded on to the plug member and forms a protective housing for the upper end of the needle valve. Cover member 66 has downwardly extending lugs 72 to which weighted levers 7 3 are fulcrumed. Each lever has a rounded end 74 which fits within the groove 69 and a weighted end 75 which rests upon the top of a bulb float 76 which rides on the surface of the oil pool in the oil reservoir. Now, it will be seen that as the oil level in the reservoir rises, the bulb float also rises and lifts the weigh-ted ends of the lever members.

This lifting action on the weighted end of the levers causes the rounded ends thereof to descend carrying collar member 68 and the needle valve with them, the tapered end 77 of the needle valve thus approaching and eventually seating in the valve seat. Thus, the .oil inflow to the reservoir may be limited or entirely out off. A corresponding lowerin ers the bulb float, which permits the weighted of the oil level in the oil reservoir lowends 75 of the levers 7 3 to descend, lifting the tapered end 77 of the needle valve away from the valve seat. The oil reservoir is at such a level as to give a gravity flow from the reservoir to the tray portion of the combustion chamber. It is now seen that the oil level on the tray will tend to remain the'same as that in the oil reservoir and the maximum oil level permitted on the tray will be the maximum oil level in the reservoir at which point valve seat 62 will be closed by the tapered end of valve 63. Thus, the maximum 4 oil level permitted on the tray may be regu-,

lated and controlled. An overflow oil passage 78, shown in Fig. 2, extends from the in-' ner end wall of the reservoir block and enters the wall of the oil reservoir below the clogged or otherwise fail to operate and flooding of the tray above the maximum oil level begin, the oil level would likewise rise in overflow pipe 80 and overflow into the trip pan 82, hereafter to be described. Thus, it is seen that at no time will oil flood the-com bustion chamber to such an extent as to cause it to overflow. I The fuel flow control valve 6, as in Fig. 3, regulates the rate of oil flow to the combustion chamber and comprises an autotapered end 84 adapted to seat within valve seat 27. A pipe 85 made-of non-magnetic,

metal has a threaded end 86 which is screwed into the threaded wall of the vertical passage in the reservoir block and forms a guide for the vertical valve stem. The upper end of supply pipe to the reservoir shown pipe 85 is interiorly threaded to receive hollow screw cap 87. An elongated bolt 88 having a head 89 is'secured to the upper end of the valve stem and extends through screw cap 87. A bridge member 90 secured to the top of the reservoir block by suitable means, as screws 91, extends over screw cap 87 and has a threaded aperture 92 through which "cavity formed in the reservoir block and surrounds the non-magnetic pipe 85. Lead wires 95 connect the magnet with a suitablepower source in a manner hereafter to be described.

.Since pipe 85 is of non-magnetic metal, the

lines of force set up by the inflow of current to the magnet will-not pass through it but will pass around the end thereof and exert a lifting force on valve stem 83.. Thus, it is seen that when current flows to the magnet,

the valve stem is lifted until it abuts the bottom of screw plug 87 opening the oil flow valve the predetermined maximum, and remains lifted until current to the magnet ceases to flow, when the valve stem drops back until bolt head 89 rests on screw cap 93, closing the fuel flow valveto the predetermined minimum. A cover member 96 clos- 'ing the cavity has an apert ure through which the'lead wires 95 to the coil magnet extend.

, Safety valve 7, as shown in Figs. 1 and 2, 1 comprises, a body portion 97 which contains the valve structure, and is secured by bolts 98 to the inner end wall of the reservoir block. The body portion contains an oil passage 99 leading fromthe oil supply pipe 100 to a valve seat 101. From the valve seat the passage extends out through the body portion where it terminates in an external boss 102 fitting into the open end of oil passage 20 in the reservoir block to form a tight joint and acontinuous fluid passa e from the oil block. A clean out passage 103 extends from the valve seat plunger 105 has a headed portion 106 at one end whichcoacts with valve seat 101, extends 1 through passage 107 and has a bellows arrangement 108 secured to itsother end, which permits the valve plunger to operate verticali'ly'against the flow of oil. An arm member matically operated valve stem 83 having a 109, pivoted at one end to the reservoir block by means of lugs 110 and pintle 111, carries at its other end a predetermined weight 112.

The end tr valve plunger 105 extends through.

,115 vertically to the top of the body portion and is capped by a removable plug 104. Valve pan cover and its tip end 125 is adapted to slide under and contact with weight 112.

The point of contact of the clip and weight is between the vertical plane of the cradle pivot point and cradle weight 121, so that when the trip pan slides into position and clip member 124 raises the arm weight, any jars that the burner might receive will not cause the tip of the clip member to slide from beneath the weight. When the trip pan is in position, weight 121 overbalances the cradle and pan, causing the clip member to abut weight 112, holding the arm member 109 raised and the valve plunger 105 normally raised off the valve seat. As overflow oil accumulates in the trip pan to a certain point, the trip pan and cradle become over-balanced in the other direction, one end of the pan descends and with it the weighted arm member 109, causing valve plunger 105 to seat and the inflow of oil to be shut off. A shelf member 126 is secured to the end wall of the reservoir block and extends beneath the safety valve, to conduct any leakage from the safety valve into the trip pan. A manual weight lifting device is provided to facilitate andpermit the insertion of the trip pan into the cradle once it has been removed, and comprises a rod 127 extending through the base member and having :1 lug 128 secured thereto adapted to engage the weight 112 and raise itas the rod is turned. A knurled knob 129 secured to a projecting end of the rod member facilitates the turning of the rod.

Blower housing 8 may be cast in one piece and secured to base flanges 15. A downward ly inclined tubular portion 130 directs the air towards the combustion chamber but preferably is cut short at the edge of the reservoir block. Floorpart 131 of the tubular portion has a curled over edge 132 that comes to approximate contact with the upper edge of the reservoir block and forms, in conjunction with the vertical side walls of the blower housing. a protectiveenclosure for the safety valve 7. A circumferential ridge 133 may be disposed near the edge of the tubular portion for a purpose to be hereafter disclosed. The top of the blower housing may be given a rounded form or east with a flattened top portion 1 H. as illu-1raled in vide a convenient place for attachment of the name-plate.

A suitable blower 9, designed to produce an OXGItlIIZOW stream of air of moderate velocity, is positioned within the blower housin g and mounted on an extension of the armature shaft 135 of the motor 10. 1 Shaft 135 is journaled in a side plate 136 secured to one side of the blower housing. A suitable bracket extending laterally from the side plate 136 maybe used to support the motor.

The air duct, illustrated in Figs. 5 and 6,

is formed of a collar member 138 surrounding the air opening in the side wall of the blower housing, the collar member having an inturned flange portion 139, to which is secured the curled over flanges 140 of a sleeve member 141. A cup-shaped member 142, having a closed end 143 telescoping over but spaced from the side walls of sleeve member 141, has leg portions 144 formed integral therewith and secured by means of bolts 145 -to collar member 138. A ring member 146 telescopes over the cup-shaped member 142 and is adapted to slide over the leg portions 144 thereof, closing or opening the openings 147 left between the legs, a variable amount asdesired. Incoming air enters the openings 147, passes between the wallsof the cup member 142 and sleeve member 141,'into the sleeve member and into the blower housing, as illustrated by the arrows in Fig. 6. A

damper 148 of aconsiderably less diameter than sleeve 142 is disposed therein and secured to the rod 149 journaled to the sleeve walls. When the damper is in vertical position, the sleeve is thus onlyvpartly closed. In this position of the damper, suflicient air is admitted into the blower housing and forced into the combustion chamber to support the low burning rate of combustion and still have suflicient'air left over to burn deposited carbon heretofore described. The damper is preferably automatically operated by a solenoid 150 secured to the side wall of the blower housing by a suitable bracket 151. The

damper may be operatively attached to the solenoid by means of a lug 152 secured to the rod 149, the lug having a slot 153 in which slides pin 154 secured to an extended portion 155 of the solenoid core 156. As the solenoid is energized by an electric current coming in through lead wires 157, the core is drawn up into the solenoid, lifts the end of lug 152 and opens the damper. hen the solenoid is deencrgized, the damper drops back to its normal closed position.

The lead wires from the electrically controlled oil flow valve and air valve are electrically connected to a power source and to a room thermostat. As the thermostat calls for heat. the circuit closes. solenoid and coil magnet are energized and the oil flow control valve and the air flow control valve 0 Fig. 2. to impro e its appeara'iu-e and to proare opened to their maximum capacity.

When sufiicient heat has been produced, the thermostat breaks the circuit, and the oil valve and air valve drop back to partly closed position. The blower operating motor is preferably connected to a power source in a circuit distinct from the valve and thermostat circuit.

Cover member 13, of sheet metal, saddles the combustion chamber, curves around the same and is secured at its side edges to side flanges 56 of the chamber. The front edge of the cover member seats against ridge 49 on the nose portion of the chamber. Clip 158 attached to the chamber door 47', is adapted to engage the opposite edge 159 of the cover, holding the door in open position. Thus, it is seen that cover member 13 forms a closed air passage between it and the chamber housing, directing the current of air from the blower into the nozzle apertures.

Hood member 12, of sheet metal, overlaps the adjacent edges of the blower housing 8 and cover member 13, ridge 133 on the blower, housing directing the positioning thereof. Its side edges are removably secured by suitable clip members to the burner base in such a manner as to permit easy removal of the hood for access to parts to be regulated or adjusted.

The operation of the burner is as follows Assuming that the burner has been properly connected to the oil supply tank,

' oil will flow through the safety valve,

into the oil reservoir and rise to the maximum level permitted by the float valve. From the reservoir, the oil will flow to the oil flow control valve and on to the tray of the combustion chamber, where it will tend to assume the same level as the oil level in the reservoir. Wick 44 dipped in the oil'pool formed on the tray is now ready for lighting. Trap door 47 is lifted, a lighted match inserted and the wick ignited. Sufllcient air is usually present to permit the wick to continue to burnwith a feeble flame without forced air. When the motor switch is turned on, the blower forces air into the combustion chamber through the nozzle apertures. If the damper air valve is in closed position, only a limited amount of air can enter the blower housing and be forced into the combustion chamber. This limited amount of air forced into the combustion chamber increases the rate of burning sufiiciently to keep the tray and fuel pool heated to give off a limited amount of fuel vapor. This is called the low burning rate or point of minimum burning. This is the normal condition of the burner when put in operation and heat is not called for by the room thermostat. In this condition, the electric circuit joining a power source with the room thermostat, air valve and oil valve is open at the thermostat, and no current flows to operate the air valve or the oil valve. The oil flow control valve is, therefore, closed as nearly as adjusting cap 93 permits, allowing only the minimum rate of oil flow to the combustion chamber. Air valve 148 is then also in closed position, but it is'made of such reduced size that such a quantity of air can still be drawn around the valve into the blower housing and forced into the combustion chamber as will give air in excess of that necessary to burn the limited amount'of fuel oil admitted. This excess of air in the combustion chamber at the low burning rate supplies the air necessary to burn out any accumulated carbon or foreign matter that may be in the burner. I As the temperature in the room drops, the thermostat operates to close the electrical circuit between the power source, oil valve and air valve, and causes the coil magnet 94 around the oil valve to become energized,

opening the oil valve to maximum open position. The solenoid operating the air valve is likewise energized and the air valve opened to maximum position. A condition of maximum oil flow and maximum air flow into the combustion chamber now prevails, and at these rates of air and oil flow, the oil valve port opening should be so adjusted in relation to the maximum air port opening as to give the proper mix of air and fuel vapors given 01f from the oil pool, to give the greatest calorific efliciency per pound of oil con sumed. To adjust the burner so as to get the greatest calorific efficiency at the high burning rate, an examination is made of the flame, its color and'intensity noted, and adjusting cap 87 is rotated to allow the oil flow valve to be opened a greater-or lesser maximum amount as conditions require. When the proper maximum valve opening is found for the high burning rate, the maximum adjusting cap is fixed at that point and need not further be disturbed. The minimum rate of oil flow for the low burning rate can likewise be regulated by adjusting cap 93, but should always be so set that an excess of air in the combustion chamber will always be present to give sufiicient air to burn out any overflow pipe 80 and drip into the trip.

pan. As the trip pan becomes filled, its outer end will eventually drop down, permitting the weighted arm 109 to drop and the safety valve to close, shutting off the oil supply to the burner. If the burner is in operation it will only burn until the fuel on the tray has been consumed. Before the burner can again be placed in condition for operation, the trip pan must be removed, the oil therein emptied, the pan reinserted in its cradle, and the trip manually reset, opening the safety valve permitting oil to sup ply the burner.

The burning process going on in the combustion chamber may be outlined briefly as follows. Due to the heated condition of the tray and the heat generated by the flame proceeding from the wick, the pool of oil in the bottom of the tray is constantly vaporizing. As amatter of fact, the possibility of any carbon collection is greatly minimized by maintaining the (ombustion chamber temperature at the points of contact with the incoming fuel sufliciently high to substantially immediately vaporize the oil. This action is better described by stating that the temperature of the metal in contact with the oil is high enough to prevent the oil wetting the metal surfaces except very close to its point of entrance to the chamber. The time elapsed bet-ween entrance of any particle of fuel and its complete vaporization is thus very small. It has been noted that under these conditions the release of carbon from the vapors during vaporization'is practically eliminated as contrasted to the results obtained in the common method of compargtively slow distillation from a pool of liquid uel.

The nozzle apertures in the top and sides of the housing portion of the combustion' chamber direct the incoming streams of air down along each side of the housing portion, as is illustrated by arrows in Fig. 4. The air streams hit or impinge the fuel pool along each side edge and then begin to roll across the pool surface until the oppositely directed air streams meet at the center of the pool. By this partial roll and sweep across the pool they become well saturated with fuel vapors, and when they collide at the center of the chamber, they mix and rise together. The oppositely directed incoming air streams through nozzles 54 and 55 cause the rising column of vapor saturated air to divide and curl over in opposite directions, at. the same time mixing with the incoming air. These vapor saturated air streams are also carried downwardly by the incoming air as it follows the walls of the chamber and partially rolled up therein. Fuel vapors in the center of the rolling stream of air are mixed with and absorbed by the air streams, as they roll, spiral, and advance out of the combustion chamber. When a suitable mixture of fuel vapor and air is attained, the mixture bursts into flame. As the burning progresses and the walls of the combustion chamber become suificiently heated, a very small pool results, since the oil is almost immediately vaporized. The air, it is understood, continues to sweep the sides and bottom of the combustion chamber and mixes with the rapidly forming oil'vapor. Thus, a continuous flame belches from the mouth of the combustion chamber, the flame having a rolling or whirling motion given it by the rolling and spiralling vapors in process of of combustion. By this rolling and spiralling action, a most intimate mixture of air and fuel vapor results, with consequent perfect combustion of the oil and air. H

. No carbon is given an opportunity to form or collect at any place in the combustion chamber because the inside surfaces of the walls are completely bathed with the whirling air. The nozzle apertures are so disposed along the full length of the chamber as to eliminate any dead spots or pockets 'vhere air is not in rapid motion. Downward and outward direction of the air sweeping the walls ofthe chamber is preferable because of the ease of application, because it causes concentration of rich vapors in the central portion of the combustion chamber away from the chamber walls where they would be inclined to collect in dead spots, and because the thickness of the air bath 'can be more easily controlled. The multiplicity of nozzle apertures permits the necessary volumes of air to be introduced at very low pressures and velocities, reducing the usual noise of combustion and tending to steady and improve the mixing of the air and oil vapors.

As many changes could be made in the above construction, and as many apparently widely different embodiments of this invention could be made Without departing from the scope thereof, it is intended that all mat ter contained in the above description or shown in the accompanyingdrawings shall be interpreted as illustrative and not in a limiting sense.

What I claim is 1. The method of burning liquid fuel which includes first bathing all exposed interior portions ofthe combustion chamber with entering. air, and then rolling said air against the surface of a pool of liquid fuel transverse to the fuel flow in the presence of a flame to produce a flaming combustible mixture of vapors from the fuel pool and said air.

2. The method of burning liquid fuel which includes first bathing all exposed interior portions of the combustion chamber with entering air to prevent the formation of carbon deposits'on the chamber walls, then impinging said air against the surface of a pool of liquid fuel, giving said air a rolling action transverse to a flame to producea flaming combustible mixture of vapors from the fuel pool and said air.

3. The method of burning liquid fuel which includes first bathing'all exposed interior portions of the combustion chamber where carbon may be inclined to deposit with entering air, then rolling said air against the sur face of a pool of liquid fuel transverse to the fuel flow and advancing said rolling air stream in the presence of a flame to produce a flaming combustible mixture of vapors from the fuel pool and said air. 1

4. The method of burning liquid fuel which includes first bathing all exposed in terior por-Lions of the combustion chamber with entering air, then impinging said air against the surface of a pool of liquid fuel,

giving said air arolling action transverse to the fuel flow and advancing said rolling air stream in the presence of a flame to produce a flaming combustible mixture of vapor from the fuel pool and said air.

5. The method of producing an intimate mixture of fuel vapors and air which includes first bathing all exposed interior portions of the combustion chamber with a layer of air, then sweeping said layer of air over a vaporizing pool of liquid fuel, satur at-ing said air layer with fuel vapors, and

rolling said saturated air layer against an incoming air layer.

6. The method of producing .an intimate mixture of fuel vapors and air which includes sweeping a layer of air into contact with a vaporizing pool of liquid fuel, and toward the center of said pool, saturating said air layer with fuel vapors, rolling said saturated air layer into contact with an incoming air layer and continuing the rolling action of the" respective layers until an intimate mixture of said layers is effected.

7. The method of producing an intimate mixture of liquid fuel and air which includes vaporizing said liquid fuel introducing air s reams above said liquid fuel, directing said air streams in opposite directions around the fuel vapors with consequent intimate mixing of vapor and air streams.

8. The method of producing an intimate mixture of liquid fuel and air which includes vaporizing said liquid fuel at the bottom of a heated chamber having top and side walls, and introducing streams of air along the top and sides of said chamber in such a. manner as to give a spiral rotation to said air streams with consequent intimate mixing of the fuel vapor and said air streams.

9. The method of producing an intimate mixture of liquid fuel and air which includes vaporizing said liquid fuel at the bottom of a heated chamber having top and side walls, and introducing oppositely directed streams of air along the top and sides of said chamber to produce spiral rotation of said oppositely directed air streams with consequent intimate mixing of the fuel vapor and air streams.

10. The method of burning liquid fuel at alternately high and low burning rates which includes vaporizing-the liquid fuel, and so proportioning the air to the fuel vapors as to produce the greatest calorific efficiency from the fuel consumed at the highburning rate, but to produce an excess of air at the lower burning .rate'so as to consume any possible accumulation of carbon or foreign matter introduced during the previous combustion.

11. The met-hod'of burning liquid fuel and preventing the accumulation of carbon in the burner which includes vaporizing said liquid fuel from the bottom of a heated chamber, proportioning the air flow and the'fuel flow into said chamber so as to produce the greatest calorific efficiency from the li uid fuel at the high burning rate but to produce an excess of air at the low burning rate so as to consume any possible accumulation of carbon or foreign matterintroduced during the previous combustion. 5

12. The method of burning liquid fuel at alternately-high and low burning rates which includes vaporizing said liquid fuel from the bottom of a heated chamber, proportioning the air flow and fuel flow into said chamber so as to produce the greatest calorific efiiciency from the liquid fuel at the high burning rate but to produce a correspondingly increasing excess of air as the low burning rate is approached so as to consume any possible accu- 5 mulation of carbon or foreign matter introduced during the previous combustion.

13. The method of burning liquid fuel which includes flowing liquid fuel into a chamber heated above the end boiling point of the liquid fuel to be consumed, so as to cause said fuel to vaporize substantially as it appears at the entrance of said chamber, and spiralling an air stream within said chamber in the presence of a flame to produce a flaming combustible mixture of vapors from said liquid fuel and said air.

14. The method of burning liquid fuel which includes flowing liquid fuel into a chamber so heated as to cause said fuel to vaporize substantiallyupon entering said chamber, and spirally advancing an air stream within said chamber in the presence of a flame to produce a flaming combustible mixture of vapors from said liquid fuel and said air.

15. The method of burning liquid fuel which includes flowing liquid fuel into a chamber heated above the end boiling point of the fuel so as to cause said fuel to vaporize substantially upon entering said chamber and spirally advancing two oppositely directed streams of air within said cham er in the resence of a flame to produce a flaming comliustible mixture of vapors from said liquid fuel and said air.

16. The method of burning liquid fuel which includes vaporizing a pool of liquid fuel in a combustion chamber completely bathing all exposed interior portions of the HQ combustion chamber with streams of air be fore rolling said air streams against the surface of the vaporizing pool of fuel.

17 The method of burning liquid fuel which includes maintaining a pool of liquid fuel in a combustion chamber bathing all exposed interior portions of the combustion chamber with entering air streams to prevent the deposit of carbon and foreign matter on the chamber walls, and then rolling said air streams over the surface of a pool of liquid fuel to roduce an intimate mixture of the air and uel vapors from said fuel pool.

18. The method of producing a mixture of fuel vapor and air which includes spirally advancing two oppositely directed streams of. air along the surface of a pool of liquid fuel so that they intermix with one another as they leave the pool, and causing said oppo- 6 sitely directed streams to rise together.

19. The method of producing a mixture of fuel vapor and air which includes spirally advancing two oppositely directed streams of air along the surface of a pool of liquid fuel so that they intermix when most heavily charged with fuel vapors. I

20. The method of producin a mixture of fuel vapor and air which inc udes spirally advancing two oppositely directed streams of 39 air along the surface of a pool of liquid fuel so that they intermix with one another when most heavily charged with fuel vapors, and i causing said oppositely directed streams to rise together.

21. The method of burning liquid fuel which includes first completely washing the interior walls of the combustion chamber with entering air, then rolling said air stream against the surface of a pool of liquid fuel,

40 and spiralling said air stream over said pool in the presence of a flame to produce a flaming combustible mixture of vapors from the fuel pool and said air.

22. The method of burning liquid fuel which includes first completely washing the interior walls of the combustion chamber with a layer of air and. then spirally advancing said air stream along the surface of a pool of liquid fuelin the presence of a flame to produce a fiamin g combustible mixture of vapors from the fuel pool and said air.

23. The method of burning liquid fuel which includes spirally advancing two oppositely directed streams of air along the surms face of a pool ofliquid fuel in the presence of a flame to produce a flaming combustible mixture of vapors from the fuel pool and said air, said oppositely directed streams of air intermingling' together at the center of the m pool and rising together.

This specification signed this 30th day of January, 1928.

MILTON A. POWERS. 

